1949 cub; no spark past distributor

Sun Mar 31, 2013 4:48 pm

Okay so I need some input. I had two cubs, one is a 47 that runs marginally well, the second is a 49 parts tractor with a locked up engine. and I just picked up another 49 for a song. The one I just picked up looks like somebody attempted to restore it and gave up. I bought it off of a guy who said his father left it to him a few years ago and he did nothing with it, it just sat in his yard. The motor was free, but some valves were stuck so I pulled the head and cleaned up and freed the valves. I put it back together to attempt to fire it up and it doesn't have any spark. I have spark from the mag and to the distributor cap, but nothing past that point. I pulled the cap and it and the rotor looks good, I checked the points and they look like they are brand new and the gap is good. I cleaned up the kill switch post and checked the wire and put it all back together. And still have no power past the cap.

So I am wondering if the kill switch is bad? I disconnected the wire and still nothing. Is it ground to kill or ground to run? What am I missing here?

Re: 1949 cub; no spark past distributor

Sun Mar 31, 2013 8:44 pm

G'day to you. Hmm 3 Cubs - pretty cool A new member and a member of the MCC to boot

We have a lot of resources available to our members - follow the links below, spend a little time reading the data.

sugarbush wrote: I pulled the cap and it and the rotor looks good, I checked the points and they look like they are brand new and the gap is good. I cleaned up the kill switch post and checked the wire and put it all back together. And still have no power past the cap.

I am no electrical guru, but it sounds like the mag is grounding out. Follow the circuit below. Also check the plug wires - make sure that they are solid copper and not composite core. Check the cap for trace lines. You have nothing past the cap at all? Check the condenser.

Re: 1949 cub; no spark past distributor

Sun Mar 31, 2013 10:15 pm

Welcome to the forum!

Good luck with your cub,

Re: 1949 cub; no spark past distributor

Sun Mar 31, 2013 10:41 pm

sugarbush wrote:I have spark from the mag and to the distributor cap, but nothing past that point.

Hot blue spark from the magneto coil wire to ground?

If so the problem is either in the magneto to engine timing, rotor timing within the magneto, or the distributor cap/rotor.

First thing to do is roll engine over to #1 cylinder TDC. Check to see if rotor is pointing directly at the #1 spark plug tower location on the distributor cap.

Re: 1949 cub; no spark past distributor

Mon Apr 01, 2013 4:46 am

Yes I have spark from the coil to the cap, nothing past the cap. After sleeping on it I agree it has to be the timing. I have run through static timing a dozen times and it goes as it should... I think the governor is timed correctly. I re-aligned the rotor and I think it is timed correctly. Is there anyway that the points could be put in out of time? I didn't assemble them and like I said, it looks like somebody did a lot of work before giving up on the tractor. Perhaps something in the mag it's self is incorrect?

I am going to pull a mag off of one of the other tractors and see if that works.

I learned to drive on an M growing up on a farm. I have also owned a 140 several years ago. The 1st cub was given to me by my wife's grandfather. The second one I bought as a parts tractor not running, I bought it because it had a set of cultivators with it and we grow a rather large garden. The one I am currently working on looks nice which is why I bought it... and $800.00 for a cub seemed like the thing to do. If I get it running it will be the keeper and the other two will end up being parts tractors. I have also amassed quite a collection of attachments including 1.5 sets of wheel weights, 2 cub-22 mowers, 1 c-2 mower, 2 54 grader blades and three lift arms for them. Plus the full set of cultivators midmount and rear.

Cubs are just cool, they are like the swiss army knife of the small tractor world.

Re: 1949 cub; no spark past distributor

Mon Apr 01, 2013 5:18 am

I don't have a battery in this tractor, I am using the hand crank. Do the battery cables need to be connected?

Re: 1949 cub; no spark past distributor

Mon Apr 01, 2013 5:23 am

If you have fire to the points but not out of the plug wires, I would check to see if the points were making a ground or missing the insulator where the coil and points connect or the condenser. If you have fire coming out of your plug wires but will not run, then timing.

Re: 1949 cub; no spark past distributor

Mon Apr 01, 2013 5:49 am

Ditto to what randalic said and welcome to the forum....Dave

Re: 1949 cub; no spark past distributor

Mon Apr 01, 2013 6:58 am

Make sure your rotor has good contact with the little carbon button on the inside of the cap, The back side of were the mag coil wire hooks up. I would also recomend changing out the points and condensor with eithe a new one or of a running cub. that way you know what you are working with. What color is the spark you get off your mag coil. Blue and strong or yellow and week? The threaded tower on the side of the mag is for the engine kill. If it is grounded it will ground out the spark.

Re: 1949 cub; no spark past distributor

Tue Apr 02, 2013 12:33 pm

Be sure to PRIME the oil pump since the tractor has been sitting. Welcome to the forum

Re: 1949 cub; no spark past distributor

Tue Apr 02, 2013 1:17 pm

In regards to your question about whether you need a battery connected to start the motor:

Magneto - noBattery ignition unit - yes

Re: 1949 cub; no spark past distributor

Tue Apr 02, 2013 1:20 pm

cubguy47 wrote:In regards to your question about whether you need a battery connected to start the motor:

Magneto - noBattery ignition unit - yes

I am referencing starting the motor with a handcrank--I forgot to note that.

Re: 1949 cub; no spark past distributor

Tue Apr 02, 2013 3:30 pm

Thanks for all the reply's. I am going swap Mags out this afternoon and see if I get different results.

Re: 1949 cub; no spark past distributor

Wed Apr 03, 2013 4:48 pm

So it is a Mag problem, I switched out the Mag and I now have spark to all cylinders. Now if I could get her to run...

Re: 1949 cub; no spark past distributor

Wed Apr 03, 2013 5:01 pm

You need spark, fuel, and compression in order for your cub to run, and they have to be present at the proper time. Have you verified your mag timing? Just because you have spark at the plugs doesn't mean it is timed to the governor and engine.